About Me

Manu Sharma New Delhi / Gurgaon, India

Since mid 2006 I have grappled with climate change and what it means for us. As an activist and campaigner, I sought to learn and simultaneously, attempted to influence the issues surrounding it - in technology and policy advocacy. As a consultant, I studied markets and created portfolios in sustainability services and renewable energy investment.

After thousands of hours of research, tenacious activism, working up-close with NGOs as well as the industry, delivering about two dozen public talks, countless conferences, hundreds of online discussions, a few media appearances (including Reuters, News Television, and BBC radio), and continuous evolution of my own ideas about what ought to be done - I may have found some answers but the issue remains far from being addressed.

In the despair filled world of climate change the only place I've found real and lasting hope is in a beautiful vision inspired by "The Ringing Cedars of Russia" book series by Vladimir Megre. The books have triggered a transition movement in Russia and have profoundly influenced me. I am now working towards the vision.

Climate Revolution Initiative, an RTI campaign I founded and ran for a few years is now retired. I no longer deliver talks. I still consider myself an activist though and occasionally post on Green-India group started over nine years ago.

Older entries in this blog relate to my former occupation in user experience design; long time interest in business innovation, strategy, ethics; and venture creation.

Image on top of this bar is courtesy book covers of The Ringing Cedars series published under Croatian translation. (Source)

July 24, 2013

Nothing Natural About This Disaster (Uttarakhand Floods and Climate Change)

In part-1 of multi-part series on viewing Uttarakhand floods in the context of climate change, I argue that the floods were induced by man made climate change by explaining how rising temperature influences extreme weather, showing that the world's most respected climate scientists would attribute the event to climate change, that it is in line with scientific predictions, and matches with extreme weather events being witnessed around the world.

Indian Meteorological Department calls all rains, falling over a region, that are 20% more than normal, "excess" rainfall. In the week of 13-June to 19-June, the entire state of Uttarakhand received 847% excess rainfall according to IMD.[1] This has no precedent.

In an excellent (though limited) analysis of the reasons for the disaster, R. Ramachandran writes in Frontline [2]:

What was peculiar about the monsoon this year? On June 14, the monsoon front was located over eastern India. In fact it was a trifle sluggish compared with the normal progress of the front. But within a day, the front advanced right across Uttar Pradesh and the western regions to cover the entire country by June 15, exactly a month ahead of its normal date of July 15. While the IMD had forecast a rapid advance [...], its advance right across to the west just within a day was entirely unexpected.

This has never happened in the past, according to M. Rajeevan, Adviser in the Ministry of Earth Sciences (MoES).

Despite the significantly unusual nature of the event in more ways than one, every single commentator has called the Uttarakhand floods a "natural disaster," or something to that effect, that has been aggravated by poor governance. True, illegal construction on riverbeds, unchecked deforestation, high inflow of tourists, sham environmental clearance process and a dam density that is highest in the world - are all responsible for exacerbating the damage and need to be addressed.

Without taking away from the significance of the factors that made the disaster worse, I wish to point out that we must pay greater attention to climate change, the phenomenon which induced the disaster in the first place.

Scant reports in mainstream media on climate link of the floods have cautiously talked about changing monsoon patterns [3][4] but even in reports from environmental institutions that should know, [5] little has been said on precisely how climate change influences such events, there's also fairly little about studies that had predicted disasters like these, and what they say about disasters of tomorrow. No one has connected the dots between Uttarakhand floods and other major climate anomalies unfolding around the world. Most importantly, we haven't been told who is really responsible and what implications a changing climate hold for future of the country.

How Climate Change Influences Extreme Weather

The term "natural disaster" is one of those things that has lived way past its expiry date, like Prime Minister Manmohan Singh. It's time we should let it retire into obscurity. Today almost all disasters that are supposedly natural - floods, droughts, storms, heat waves, cold waves, and forest fires (with the exception of earthquakes, tsunamis and volcanoes) - are linked with climate change.

Scientists like to put the word "anthropogenic" (man-made) before the term "climate change" [6] to signify that the phenomenon is caused by factors for which humans are responsible. Chief among them is burning of fossil fuels that emit greenhouse gases that trap heat in the atmosphere. Fossil fuels like coal, natural gas, oil and its various derivatives are consumed to power every day of our lives from the home in which we wake up in the morning, to the air conditioner that keeps us comfortable at office, the car that takes us there, and the stuff we buy at shopping malls.

None of this, of course, is "natural." As Joel Salatin, a self-described "Christian-libertarian-environmentalist-capitalist-lunatic-Farmer" and a personal hero, says in his book [7]:

For the first time in human civilization, you can flip on a switch or clench a nozzle to get energy from who knows where, turn on a faucet and get water from who knows where, send the sewage out a pipe that goes to who knows where, and build a house from materials that came from who knows where. Folks, this ain’t normal.

Over the past two centuries or so human beings have veered far beyond the path of our natural existence and we're now seeing its consequences. Back to topic, the most pertinent question here is this: "Is climate change solely responsible for causing Uttarakhand floods rather than natural factors?" Ask any climate scientist and you will get no for an answer. It's the wrong question. Instead, a good question would be: "Is it fair to say that Uttarakhand floods would have been less severe if there was no climate change?" All scientists would answer yes to that.

Our weather is a complex beast. No extreme weather event is "solely" caused by climate change. Such events are caused by a combination of what's called "natural variability" - the natural processes of a normal climate and rising temperature due to climate change. For thousands of years life has existed and thrived on this planet in a climate that has remained largely stable.[8] But less than two centuries of fossil fuel consumption has led to a warming world.

Rising temperature does to global weather patterns what drugs do to an athlete. It boosts their performance. In scientific terms, you could say, climate change amplifies natural variability. But when an athlete takes drugs before a track event and creates a world record, can you say to what degree were the drugs responsible?

It's the same with climate change. When an extreme weather event strikes, it is impossible to tell the share of climate change and that of natural variability in causing it without studying the event in detail. What we know for sure is rising temperature increases the odds of extreme weather events. If you rate all extreme events in a normal climate on 1 to 10, many 5's would be converted to 8's in a warming climate. If there is a rare event that rates 9 in normal climate, under rising temperatures it may go up to level 13 or 15 - an intensity and scale you cannot imagine in normal climate. Such records are made when both climate change and natural variability are moving in the same direction. This is what seems to have happened in Uttarakhand.

Scientists Knew This Was Very Likely to Happen

Scientists have long predicted that as temperature continues to rise this century the intensity, as well as, frequency of extreme weather events will rise with it. The Intergovernmental Panel on Climate Change (IPCC) — a conservative body of scientists who examine existing scientific studies and whose every word is debated by government representatives in its panel — has been saying since 1990 that climate change is unequivocal.[9]

Its 2007 Synthesis report warned that "continued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century."[10] The report predicted, among other things, of "increase in frequency of...heavy precipitation" (rain, snow, hail or their combination) specifically in higher altitudes like the Himalayas.[11] It further said that "disruption of settlements, commerce, transport and societies due to flooding: pressures on urban and rural infrastructures; loss of property" is to be expected. A conservative way to state what happened in Uttarakhand.[12]

In fact an RTI application filed by Climate Revolution Initiative with the Ministry of Environment in 2009 had sought to know whether the central government acted on the IPCC warnings and conveyed them to state governments to prepare for adaptation. As can be expected, the ministry had issued no such advisory.[13]

In 2009, Government of India constituted its own body of scientists named 'Indian Network on Climate Change Assessment' or INCCA to look into published research on climate change.[14] In executive summary of its report #2 published in November 2010, a key result listed in section 13 was titled "Impacts of climate change on floods." It warned of a significant increase in the magnitude of floods. And said the following [15]:

this has a very severe implication for existing infrastructure such as dams, bridges, roads, etc., in the [river basin] areas.

In 2012, IPCC published a special report on extreme events or SREX called 'Managing the Risks of Extreme Events and Disasters...'[16] It says "evidence from observations gathered since 1950" show the number of heavy precipitation events are rising; losses from weather and climate disasters are increasing; that in future, we can expect "substantial warming in temperature extremes"; and that "frequency of heavy precipitation or the proportion of total rainfall from heavy falls will increase."[17]

After a record-smashing "Angry Summer" Australia endured in 2012-2013, which brought heat waves, brush fires, and record maximum temperatures the country has ever seen, researchers at the University of Melbourne were tasked to look into future weather patterns. In a paper published earlier this month they conclude that Australia is five times more likely to see extremely hot summers and half the blame can be laid at the door of greenhouse gas emissions.[18]

While science can tell us broad trends going decades into future, it cannot tell us when and where climate impacts will occur. To an extent "where" can be determined by detailed climate vulnerability assessment studies but "when" is much harder to know in advance. Climate adaptation will be looked at in a later post.

Climate Change Has Role in Every Extreme Weather Event, Say Scientists

Records and events around the world bear out scientific predictions. May 2013, for example, was the 339th consecutive month in which the temperature of the entire globe exceeded the 20th-century average, according to National Climatic Data Centre (NCDC) based in Asheville, North Carolina, U.S.[19] Think about that for a moment. Since 1984, average global surface temperature for every single month has been greater than 1901-2000 average. The odds of that occurring by simple chance is a number "considerably larger than the number of stars in the universe."[20]

If the planet was not warming, one would expect the number of occurrences of record maximum temperature and record minimum to be about the same. For U.S, until 1970's that was the case. But by the year 2000, the ratio of high temperature records in the country was twice as much as low temperature records, says Kevin Trenberth who heads climate analysis at National Center for Atmospheric Research (NCAR) at Boulder Colorado, U.S. By 2012, maximum temperature records were being created ten times more frequently.[21]

Earlier, scientists used to hold the view that no single climate event can be attributed to climate change. But that view is changing. Three years ago, Trenberth, in a presentation to scientists argued that we should assume global warming plays a role in every climate event, then ask how significant is that role.

In August 2010 the US National Oceanic and Atmospheric Administration along with the UK Met Office's Hadley Centre organised a workshop on attribution of climate events. In it Myles Allen, another reputed scientist who heads Climate Dynamics group at Oxford university department, argued that it's no longer appropriate to say that you can never blame an individual weather event on climate change.[22]

In July 2011 climate researchers from Britain, the United States and other parts of the world announced a new international alliance that aims to investigate exceptional weather events.[23] They believe that it is no longer plausible merely to claim that extreme weather is “consistent” with climate change. Instead, they intend to assess each unusual event in terms of the probability that it has been exacerbated or even caused by the global temperature increase.

In September 2011 a press teleconference held by a renowned group of climatologists and weather experts made it clear: "All weather events are now influenced by climate change because all weather now develops in a different environment than before." [24]

James Hansen, world's most respected climate scientist, who until recently headed NASA's Goddard Institute for Space Studies in New York, U.S, goes a step further. Based on a purely statistical analysis of historical weather data, he says even without investigating individual extreme heat wave events one can say they were "caused" by climate change.[25] Hansen's study showed extremely hot temperatures covered less than 0.2% of the planet between 1951 and 1980. By 2012, those temperatures covered about 10% of the land area - a fifty-fold increase already.[25-A]

Hansen says scientists need not be defensive about linking individual weather events directly to climate change. "To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change," he wrote in August last year describing his results.[26] [27]

In July 2010 Russia burned. Some called it a once-in-1000-year heat wave, others said it is the worst heat wave ever in Russian history.[28] [29] Forests caught fire, crops were destroyed and capital city Moscow got enveloped in smoke with people walking around in masks and feeling like "smoked fish in an oven".[30] [31] [32] More than 50,000 died from respiratory illnesses and heat stress that year.[33]

Soon after, a scientific study was undertaken to investigate the factors responsible. The scientists used a new approach for crunching climate data called Monte Carlo modeling, which reports say, "is a tool for investigating tricky, probabilistic processes involving both defined and random influences: Make a model, run it enough times, and trends emerge."[34] Their conclusion was categorical: "80% probability that the 2010 July heat record would not have occurred without climate warming."[35]

Scientists at Germany's Potsdam Institute for Climate Research used physics, statistical analysis and computer simulations to link extreme rainfall and heat waves to global warming. They conclude that "It is very likely that several of the unprecedented extremes of the past decade would not have occurred without anthropogenic global warming." The study said that "the high amount of extremes is not normal."[36]

Another study conducted by Munich RE, the world's largest reinsurance firm, says the number of natural disasters per year has been rising dramatically on all continents since 1980 with the largest increase in North America where countries have been battered by hurricanes, tornadoes, floods, searing heat and drought. It says climate change is driving the increase and predicts those influences will continue in years ahead.[37]

Uttarakhand Floods Match Pattern of Extreme Weather Events Worldwide

Flood fury in Uttarakhand this year matches the pattern of climate change induced extreme rainfall and flood events in recent years in different parts of the world. In 2010 monsoons, one-fifth of Pakistan was under water killing close to 2000 people and damaging $43 billion worth of property.[38] Thailand, Combodia, Myanmar and Vietnam were all severely flooded in 2011.[39] The same year El Salvador in central America saw more rains in ten days than in entire year.[40]

Ten Years of Flooding in China

China has always been prone to flooding in the monsoon season.[41] Flooding in China, according to observers, is distinctive in that it is not limited to a single incident in a limited area. It is a series of individual flood disasters occurring over a large number of provinces, "with each province measuring the size of a European country." Over the last few years massive flooding is occurring with regularity and intensity not seen before.

Over the last ten years, every single year saw floods in China.

2012: On 21st July capital Beijing was hit by the heaviest floods since records began. It brought the city to a halt, led to evacuation of 57,000 people, took lives of 79 and caused damage worth US $1.6 billion. It was part of series of floods that began in Spring.[42] [43]

2011: In June to September central and southern China saw series of floods inundating 12 provinces while leaving others in drought. The floods affected 3.6 crore people while killing 355 and resulting in damage of US $6.5 billion.[44] [45] [46] [47] [48]

2010: Floods and landslides from May to September broke all records as it affected 28 provinces leaving close to 3200 dead, over 1000 missing, affecting crops over 97,200 square km, destroying over 13 Lakh houses, leading to evacuation of over 1.5 crore people and destroying US $51.4 billion of property.[49] [50] [51] [52] [53]

2008: Fifteen provinces in Eastern and Southern China were flooded for around 15 days of torrential rain and landslides causing over 200 people to die, forcing 13 lakh to evacuate and destroying US $2.2 billion of property.[56] [57] [58]

2007: Massive flooding from June to September caused by torrential rains and overflowing rivers affected 24 provinces, autonomous regions and municipalities with 200 million people resulting in more than 1,000 casualties. Some claimed it to be worst flooding in 80 years.[59] [60]

2006: In the most serious disaster since 1998, over 3000 people died in China due to Typhoons, floods, landslides and hailstorms. More than 1.3 crore sought emergency shelter or were evacuated.[61] [62] [63] [64]

2005: Flooding devastated 27 provinces across the country leaving some 134 million people affected. 910 people were reported dead, over 830,000 houses destroyed and more than 9.5 million hectares of farmland submerged.[65] [66] [67]

2004: In June and July 2004 Guangxi Autonomous Region experienced serious flooding that affected at least 3.69 million people, with 76 people losing their lives. 57,000 rooms were destroyed with 398,380 tons of crops lost.[68] [69]

2003: Over 2 Lakh homes collapsed and another 530,000 damaged after pounding rain in China's Shaanxi province, where 123 died or went missing between August and October. An unusually long flooding season continued till October.[70] [71] [72] [73]

India too saw a number of floods over this period. The state of Bihar regularly witnessed large flooding, particularly in the year 2004, in 2007 when several other parts of the country were flooded too along with other parts of South Asia and in 2008 when Kosi embankment broke and inundated large areas of the state affecting 23 Lakh people.[See Update 25-Jul] We can't forget Mumbai, of course, which saw 1000 mm of rain in a 24 hour period in 2005. In 2010 Leh witnessed a cloudburst killing 200 even though it's a sparsely populated cold desert that hardly sees any rainfall all year.

So far I've listed only flood events. The number of heat waves, forest fires, storms, droughts and other extreme weather events over the last few years in various parts of the world is far too large. Some people have a new term for this: global weirding. As Tom Friedman puts it, "The weather gets weird. The hots are expected to get hotter, the wets wetter, the dries drier and the most violent storms more numerous."[74]

Even as Uttarakhand floods were unfolding, other regions of the world were experiencing impacts of extreme weather of varying intensity. If there is one common denominator with all of these stories it is the fact that none were reported in mainstream print and TV media in India. Consider the sample below.

June 2013: Alberta, Canada Sees Worst Floods in History

Heavy rainfall led to extensive flooding in multiple cities in Alberta province of Canada as several of its rivers swelled to many times their peak flow. Floods displaced or evacuated over 1 Lakh people and led to deployment of Canadian Armed Forces to help in relief work. Damage was estimated to be (Canadian) $3 billion to $5 billion, which is 20-30 times the amount of damage caused by the second biggest floods in the region in 2005.[75] [76] [77]

June 2013: Central Europe Faced Floods

Several parts of central Europe mainly Germany, Austria and Czech Republic but also Hungary, Poland, Slovakia and Switzerland were caught in floods as two main rivers Danube and Elbe and their tributaries became swollen after heavy rainfall leading to floods along their banks. One region in Austria saw as much rain in two days as it would in two months. Overall losses are estimated to be US$16 billion.[78] [79] [80]

June 2013: U.S. Witnesses Large Forest Fires and Other Extremes

State of Colorado witnessed second largest forest fire in its history by area.[81] Started on June 20, it merged with two other fires a few days later and covered 110,405 acres in total. Other parts of the country from New Mexico to California and Idaho were also reported to be witnessing forest fires. Even Alaska saw forced evacuations of hundreds of citizens and animals due to a wildfire.[82]

Although immediate cause of forest fires can range from lightning strike to an Army artillery exercise, forests are more susceptible to catching fires due to climate change as rising temperature sucks moisture out of the air, out of ground and out of the trees.[83] [84] In other extremes witnessed this month in U.S, storms were lashing more frequently and tornadoes were getting more powerful as the one-and-half minute ABC news clip shows (video taken down by member).

The New York Times is calling it the new normal — an increasingly hot and dry West, resulting in more catastrophic fires.[85] Scientists say that the recent fires are hotter, more enveloping, and that they are killing far more trees.

July 2013: Southwest China Floods

In late June and early July heavy rains lashed on Sichuan province and other parts of southwest China killing 58 and disrupting lives of 60 Lakh people. The rains were described as heaviest in the region since records began in 1950s.[86] Multiple landslides following the rain buried dozens of people. In another part of the country, Eastern China, 5 Lakh people were forced to evacuate in anticipation of torrential rains brought along with Typhoon Soulik.[87]

May-July 2013: Russia Battered With Drought

Large parts of Russia have been battling drought conditions since May this year due to higher than normal temperatures. Russia has had a long relationship with drought which makes an appearance very few years. This time though Russian grain production has been affected for the fourth year in a row by weather maladies. As can be seen in the graph below, Russian crop projection is down to 20-40% in most areas. Daytime temperatures have been so high that the Government health officials called on people to take an afternoon break to limit strenuous work and sun exposure during the hottest part of the day.[88] [89] [90]

Some scientists have claimed that the floods in Europe and droughts in Russia could be linked with melting in the Arctic summer ice. Arctic region experiences melting of sea ice (floating ice) every summer and regains it in winter. Since 2005 though the rate of melting has accelerated to several times the previous years. In 2007 extent of melting shocked scientists as it was more than 22% over the previous record low.[91] In 2012, it set a record even lower.[92] This melting is decades ahead of projections in IPCC 2007 report.

Scientists have suggested that this is disrupting the normal flow and position of jet stream which influences weather patterns worldwide. An AFP news release from June 5th explains[93]:

Leading the charge is the Potsdam Institute for Climate Impact Research (PIK) near Berlin, which says a low-pressure system that dumped the rain [in central Europe] was locked into place by a disturbance with a global wind pattern. "We think it is linked to the current drought conditions in Russia as well," Stefan Rahmstorf, PIK’s professor of ocean physics, told AFP.

Rahmstorf and colleagues introduced "wave resonance theory" in a paper earlier this year that has gained a lot of traction with climate scientists:

Normally, air moves around the mid-latitudes of the planet in the form of waves, oscillating irregularly between the tropics and the poles, Rahmstorf explained. The main force behind this movement is the big temperature gap between the frigid Arctic and the warmer southerly latitudes. Like a pump, this differential helps to force air northward or southward.The problem, though, is that the Arctic is steadily warming — last year, its summer sea ice hit its lowest extent on record — so the temperature difference is declining. As a result, according to the theory, the wave movement diminishes. At a certain point, pressure systems stay locked in place, causing a weather pattern that persists wretchedly.

In a key statement Rahmstorf adds that the "planetary wave resonance is not a local effect but spread around the whole (northern) hemisphere." He argues that when "resonance" episode occurs, half a dozen peaks and troughs of high or low pressure form around the northern hemisphere. "This explains why some parts of the world become unseasonably hot or cold and others unusually dry or rainy," said Rahmstorf.

The purpose of including this section is not to claim that record Arctic melting is responsible for Uttarakhand floods but to draw attention to a phenomenon which could be connected and which requires research. Since like Europeon floods, heavy rainfall in Uttarakhand is also linked with a low pressure system,[2] that was locked into place[94], this aspect needs to be seriously investigated.

In Conclusion

Uttarakhand floods cannot be termed as a "natural" disaster. Since we know how climate change influences extreme weather events; we know it is consistent with scientific predictions; we know climate change contributes to every extreme weather event today; and finally, because similar unusual and extreme weather events attributable to climate change are unfolding all across the world; a more appropriate descriptor would be "a disaster induced by man made climate change."

Update 25-Jul: Himanshu Thakkar of SANDRP comments below that Kosi embankment failure of 2008 was more due to human error rather than extreme rainfall. If his data of below average rainfall in the area is correct, the event cannot be blamed on climate change. That said, the same year Assam, Western Maharashtra and Andhra Pradesh also witnessed flooding due to heavy rainfall. In total, according to government data, over 2400 people died in monsoon floods that year. Deaths due to Kosi is said to be around 400.

Update 05-Aug: In a comment below Nagraj Adve writes: "Unfortunately, we still cannot link single rain events to climate change though as you persuasively argue, it is likely they like Uttarakhand are linked." I would respectfully disagree. I think it has long been known that warming will lead to heavy rainfall events. Here's a paper from 1992 and one from 1993 investigating climate change influence on rainfall. Today in mid 2013 there is already extensive research on this.

In a 2011 paper titled "Human contribution to more-intense precipitation extremes", researchers from Canadian and UK universities argued that "human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas." It went on to add that "the impacts of future changes in extreme precipitation, may be underestimated because models seem to underestimate the observed increase in heavy precipitation with warming." Joe Romm of Climate Progress blog called it a "seminal" paper and BBC report on the study was titled "Climate change raises flood risk".

Another study titled "Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000" published at the same time looked at flooding of UK and Wales in 2000 and concluded that GHG emissions were "very likely" ( >90% probability) responsible.

A study published in April this year titled "Probable maximum precipitation and climate change" found that "continued course of high greenhouse gas emissions would influence the potential maximum precipitation." See coverage on Climate Progress blog titled: "When It Rains, It Pours: Study Confirms Climate Change Will Keep Driving More Intense Precipitation."

Apart from this, we also know that climate change raises risk of glacial lake outburst which was also witnessed at Kedarnath in Uttarakhand. A 2010 report from U.S. Geological Survey, which came out when one-fifth of Pakistan was under floods, stated that Himalayan glacier retreat due to climate change "increases the likelihood of outburst floods that threaten life and property in nearby areas."

Then there are several studies specifically on Indian Monsoon that link climate change to extreme rainfall events. Prof. Dr. Anders Levermann at Potsdam Institute For Climate Research replied to a query saying that "variability of the Indian monsoon system is very likely to increase under global warming. We have recently shown that all models of the new CMIP-5 model inter comparison afford show such an increase in variability. Overall higher rainfall during the monsoon season is to be expected." He cited two of his recent studies in support of increase monsoon rainfall and increased monsoon day-to-day variability respectively.

So science is pretty clear that climate change leads to extreme rainfall. That said, one can well argue that every extreme rainfall still cannot be attributed to climate change and one may technically be correct unless there is evidence. But what I have tried to establish in this post is that we do no necessarily need this evidence! As observers we do not need to CONCLUSIVELY PROVE climate link for each single event because it fits a broader PATTERN of increased frequency of such events which is consistent with climate change.

10 Comments so far

Anonymous:

I am wondering why people do not understand these issues with more care. While I was reading the post, it was making sense to me. Of course there is a difference between understanding and acting. After all this I must say, that we must act.

Thanks, it is indeed very good to see this connection of dots. Only a word of caution. I am not sure if every climate linked disaster can be connected with climate change. One example is the breach of Kosi embankment in Aug 2008. When the embankment breached, the flow in the river was below 1.5 lakh cusecs, when the river is expected to get upto 9.5 lakh cusecs of floods in monsoon. So that disaster cannot be linked to climate change, it was basically because of lack of maintenance of the embankment. Similarly, in current Uttarakhand disaster the proportions increased because of a lot of acts of commission and omission by humans.

Thank you for your comment, Himanshu Thakkar. As I show in the post, scientists are clear that every extreme weather event (particularly heat waves, floods and droughts) is attributable to climate change. If the flow in Kosi river in 2008 was below average, and I trust your figures, then you're correct it cannot be linked with climate change. I will remove the reference and add a note. Thanks for this.

Hi Manu, I read the blog post properly and it is really excellent. Covers a lot, very well written, nice analogies and metaphors, and a wide coverage of the science and recent disasters. will forward it widely. One qualification: Hansen's 3-sigma warming re extreme events extend only to temperature anomalies and not extreme rainfall. Unfortunately, we still cannot link single rain events to climate change though as you persuasively argue, it is likely they like Uttarakhand are linked. Even the Bombay rains cannot be conclusively said to be due to GW though it is very very likely.See the mail from James Hansen making this clear. I had emailed Hansen about Uttarakhand.

Nagraj

Hansen's email below.

I think that modeling and theory suggest that, in addition to higher global temperature promoting increased average rainfall, the distribution of moist convective events, shifts toward having more of the moisture in larger events. In case of precipitation events, unlike seasonal mean temperature anomalies, it may be very difficult to make an attribution case for a single event and I suspect that the data are not good enough to define a distribution and its changes. However, I am not an expert in this topic, so you had better consult one -- I copy Tony Del Genio, who is the most expert of people I know.Jim Hansen

Yet another study, this one published just a week ago that links climate change with extreme rainfall and flooding.

Excerpt from a news report below:

Heavy and prolonged rainfall will cause both more frequent and more severe flooding across the UK and the rest of north-west Europe as the atmosphere continues to warm, say British and American scientists

The study of these "atmospheric rivers", published in Environmental Research Letters, pins the blame for the increasing flood risk firmly on man-made climate change and says the same problem will afflict other parts of the planet.

The researchers describe how atmospheric rivers carry vast amounts of water vapour around the Earth, delivering heavy and prolonged rainfall, particularly to mountainous areas. They were responsible for the protracted winter and summer floods in the UK in 2012, which caused an estimated $1.6 billion (£1 bn) in damage.

In a warming world the atmosphere can carry more water and the research showed that the rivers, typically running a kilometre above the Earth, 300 kilometres wide and thousands of kilometres long, would become larger and capable of delivering even bigger quantities of prolonged rainfall.

An example of their potential danger is the atmospheric river that caused the severe flooding on 19 November 2009 over north-west Britain. As it approached the coast it was transporting a moisture volume 4,500 times the average gauged flow of the river Thames through London.

Thanks for putting together so much reporting and research on climate change and extreme weather events. It is most helpful. I had not heard of 'atmospheric rivers'. If it is true that the moisture-carrying capacity of the atmosphere grows as the latter's temperature rises, it certainly strengthens the link between climate change and the frequency, intensity and duration of rainfall and consequent flooding. If there is more investigation of this, please do post here. Thanks again!